<!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8">
  <title>10_ComponentLife</title>
</head>
<body>
<div id="example"></div>

<script type="text/javascript" src="../js/react.development.js"></script>
<script type="text/javascript" src="../js/react-dom.development.js"></script>
<script type="text/javascript" src="../js/babel.min.js"></script>
<script type="text/babel">
  /*
  需求: 自定义组件
    1. 让指定的文本做显示/隐藏的动画
    2. 切换时间为2S
    3. 点击按钮从界面中移除组件界面
   */
  class Fade extends React.Component {

    state = {
      opacity: 1
    }

    constructor (props) {
      super(props)
      console.log('constructor(): 创建组件对象')
    }

    componentWillMount () {
      console.log('componentWillMount(): 初始化将要挂载')
    }

    componentDidMount () {// 在此方法中启动定时器/绑定监听/发送ajax请求
      console.log('componentDidMount(): 初始化已经挂载')
      // 保存到当前组件对象中
      this.intervalId = setInterval(function () {
        console.log('--------')
        // 得到当前opacity
        let {opacity} = this.state
        // 更新opacity
        opacity -= 0.1
        if(opacity<=0) {
          opacity = 1
        }
        // 更新状态
        this.setState({opacity})
      }.bind(this), 200)
    }

    componentWillUpdate () {
      console.log('componentWillUpdate(): 将要更新')
    }
    componentDidUpdate () {
      console.log('componentDidUpdate(): 已经更新')
    }

    componentWillUnmount () {// 清除定时器/解除监听
      console.log('componentWillUnmount(): 将要被移除')
      clearInterval(this.intervalId)
    }

    removeComponent = () => {
      ReactDOM.unmountComponentAtNode(document.getElementById('example'))
    }

    render() {
      console.log('render() 渲染组件')
      return (
        <div>
          <h2 style={{opacity:this.state.opacity}}>{this.props.content}</h2>
          <button onClick={this.removeComponent}>不活了</button>
        </div>
      )
    }
  }
  ReactDOM.render(<Fade content="react学不会, 怎么办?"/>, document.getElementById('example'))
</script>
</body>
</html>
